This new text is a guide for understanding, envisioning, and acting on the lessons of English as a Lingua Franca (ELF) research in English Language Teaching (ELT) classrooms. The volume is the result of the cooperation of an international team that includes members involved in research, teacher education, and classroom practice.This collection bridges theory, methodology, and real-world application of ELF research for the first time. Chapters offer a variety of practical perspectives and support teachers to better prepare their students for the reality of how the English language is used around the world today. With close attention to the nuts and bolts of teaching – as well as useful features for further investigation, discussion, and application – this book will be a helpful, practical resource for current and prospective English language teachers, teacher trainers and mentors, and curriculum designers.